1971 Buick GS 455 Stage 1

Feature Article from Hemmings Muscle Machines

We're all familiar with the plight of the average muscle car. Driven off dealer lots and showroom floors everywhere, they were commuters and part-time racers, or full-blown dedicated competition machines. In some cases, the vehicles we now covet have traversed both segments of usage before the resurgence of their popularity. As these machines traveled through the years, many accumulated commonly seen battle scars, often the result of teenage abuse, parts swapping, misguided modifications or even abandonment. Yet, somehow, a number of these street machines avoided the darker side of a performance car's existence.
One of the fortunate ones is this month's subject: a Bittersweet Mist 1971 Buick GS. It's one of just 81 convertibles that left the assembly line equipped with the famed 455 Stage 1 engine option. And because it was sold new in Quebec, courtesy of GM of Canada, there is unquestionable documentation substantiating its as-built claims. Had this Buick's second owner--also from Quebec--been aware of this scant number, he might have been more reluctant to take it to the drag strip and rev its engine well into the red during the mid-Eighties. But the rarity of such machines was not so widely known in those days, and so the GS was raced for leisure, and that's where Keith Diabo and his brother, Duane, first discovered it.
Keith, a performance Buick enthusiast practically from birth, to hear him tell it, is co-owner of Gran Sport Autobody in Kahnawake, Quebec, along with Duane. Keith described his first encounter with the GS for us recently.
"After watching [the owner] race, we walked over and started to talk about the car. It was running in the 14.20s at over 100 MPH, but he was disappointed, saying that he 'thought it would be faster.' Our suggestion was to scrap the street radials--which were not hooking up till half-track--in favor of slicks. Later, we heard it was for sale; while examining it, I was amazed to find that it was a real, matching-numbers Stage 1 GS."
It didn't take long for Keith to purchase the mechanically unaltered Buick in 1987, at which point he proceeded to pull the original engine, BB-coded (Stage 1) Turbo Hydra-Matic automatic transmission and 3.42:1-geared rear differential from the chassis and put them in safe storage. In their place went a similar transmission and differential, as well as a mild, stock-appearing engine. For the next seven years, Keith drove, and raced (turning consistent mid-12s) the rare convertible until he sold it, original drivetrain included, to noted Buick performance enthusiast and friend, Bob Lindquist.
"Considering where the car had been located its entire life, it was still relatively solid, complete and looked good, even up close," said Keith of the car at that time. "Bob purchased the GS knowing that it was due for a restoration rather than just another repaint, as had been the case prior to my ownership. Initially it was to be restored as a high-quality driver over a prolonged period of time."
There were several reasons for the extended approach to the Buick's restoration, chief among them an effort to help distribute the cost of the project. Then there was the documentation aspect. Because the car had never been completely disassembled at that point, there was a good chance that Keith, Duane and a third brother, Corey, would uncover factory stampings and paint dabs that would come in handy during reassembly.
And then there was the collecting of replacement parts. Since this was in an era when reproduction material was still limited in comparison to today, the search was on for either NOS or clean, used components from donor cars.
Disassembly commenced soon after the title traded hands in 1993, starting with the removal of the A-body's brightwork: bumpers, trim, grille and all exterior lighting. Below the rear wheel-lip moldings lay some rust that would need to be addressed. Nearly the entire interior and trunk were stripped out next, exposing noticeable areas of corrosion on the floorboards and trunk pan. Removal of the electrically operated top was then accomplished before the decklid, hood and the inner and outer front fenders were unbolted and stowed.
Rather than separate the body from the frame at this point, Keith and his brothers opted to strip the body of its layers of paint via sanding and chemical methods, and then tackled the required floor work in the trunk. "Each support rail directly above the frame rail needed to be cut out, as well as a small corresponding section of the floor; these rails are where the rear body mounts are located, which had been damaged by rust. We did as little cutting as possible in order to maximize the amount of original metal saved. By installing new braces from a donor before removing the body, we could make sure the structural integrity had not been compromised and have a proper alignment already in place for the body mounts and associated bushings come time for reassembly," remembered Keith.
Focus then shifted to the rear wheel lips, as well as some rot-through on each inner wheelwell. Damage to this region was not nearly as significant, so it was a relatively simple matter of acquiring proper geometry with the replacements cut from a donor originating out of Texas. Using a MIG welder, each piece, including the aforementioned trunk repairs, was butt-welded into position, first with spotwelds, then fully welded in alternating sections to avoid panel warpage. The welds were then ground smooth on each side for a seamless transition. This same process was used to correct damage to the driver's side floorpan as much of it was eliminated using a replacement section from a donor, as well.
Structural points of interest rectified, Keith used braces to further strengthen the convertible's body shell to prevent unwanted flexing while he and his brothers lifted it off the frame and placed it on a body dolly. "It was strong enough to be positioned on a rotisserie, but we felt more comfortable placing it on the dolly because of the project's timeline; we simply didn't want to take a chance on it flexing while it was suspended for such a long period. We also had to fix the two front body-mount brackets at the base of the firewall; it was an extensive effort that needed to be done with extreme precision, and the dolly made that possible. A lot of man-hours went into correcting the body ailments alone," said Keith.
While the body was being subjected to its restoration, the frame was carefully stripped of the remaining running gear, brake and fuel lines, and suspension system before it was sandblasted to bare metal. Fortunately for all involved, no damage was uncovered in the process. After a thorough cleaning to ensure that remaining particulate was not on any surface, PPG black epoxy primer was applied, followed by semi-gloss PPG paint--after a proper cure time--to replicate the factory finish. It was at about this time when Bob asked that, due to the rarity and numbers-matching aspect of the GS, the project shift gears from ultra-clean driver to a concours-level showpiece.
With that in mind, great care went into the completion of the chassis. The list of NOS parts utilized for the chassis alone is extensive, and somewhat astonishing, including front upper control arms with factory-riveted ball joints; complete front and rear bushing set; steering linkage; front rotors; front backing plates; rear drums, shoes and other internals; rear wheel cylinders; and rear upper and lower control arms. In fact, it would almost be easier to list what wasn't replaced during the chassis refurbishment: The front calipers, the steering box and the 3.42-geared Positive Traction differential were all rebuilt and refinished. Pre-bent reproduction brake lines were purchased from Classic Tube; however, they were secured into position with NOS clips, as was the new fuel line.
As the chassis restoration progressed, work began with the rebuilding of both the original engine and transmission. The former of the two received a standard .030-inch overbore to rid the cylinder walls of wear, while the original carburetor and distributor were rebuilt with NOS parts, as well as the starter, alternator and pulleys. The original camshaft and crankshaft were retained, as were the original re-detailed exhaust and intake manifolds. NOS valve springs were used in each cylinder head and an NOS water pump was installed; NOS gaskets throughout completed the reassembly phase.
Similar treatment was bestowed upon the Turbo Hydra-Matic transmission. The BB-coded unit--indicating it was specific to the Stage 1 engine option--was cleaned and rebuilt to original specifications, with its extra clutch plate and original torque converter.
Now that the chassis, engine and transmission were checked off the list, the team got to work returning the repaired yet still disassembled body to its former glory. The bare steel body was prepared for finishing by first using a metal cleaner and then a conditioner. Instead of laying a typical skimcoat of body filler as the next step, Keith and his brothers take a different approach. "We apply several layers of zinc-based PPG epoxy primer. It's a lengthy process, because we need to let the primer cure before block-sanding it with 400-grade paper. After the last layer of epoxy primer has cured and been sanded, then we apply a primer sealer," he commented.
Once all of the body panels have been prepared for paint, their second date in a spray booth is delayed for what Keith described as a critical step in their restoration process: the test-fit of the body on the chassis. As told by Keith, "We completely assemble [the body and chassis of] any car we restore in order to properly set the panel gaps, noting the number of shims that may be needed on anything from the fenders to the decklid. It's a preventative measure in the sense that we won't have to wrestle with panel fitment issues later, which could lead to accidental damage to the finish. Once that's done, we disassemble it yet again and send the body to paint."
The Buick's body panels were then painted individually using PPG matched to the factory hue of Bittersweet Mist in several coats before a series of PPG clearcoats followed, with exception of the shell's underside, which received a couple of coats of PPG semi-gloss black paint to match the factory finish. After permitting proper cure time, the three Diabo brothers embarked on the arduous task of wet-sanding the finish, first with 1500- and then 2000-grade paper. The final paint step for the ultimate sheen is polish and buffing. It's a start-to-finish process that lends to the extreme longevity of the final finish, according to many of Gran Sport Autobody's customers.
Although, at this point, it would seem as though all that remained was a simple matter of reassembly, the Buick was far from finished. As is typical, the body was carefully lowered into position on the frame and secured with the properly labeled, bagged-and-tagged bolts and shims identified during the test fit. As expected, everything fit properly, without a hitch, including the front inner wheelwells.
The GS next received the wiring harness, while all of the associated holes in the firewall were still accessible. With the fenders protected, the engine and transmission were then installed as a unit, followed by the other engine bay items: master cylinder and power brake booster, NOS clutch fan, radiator (on the Buick's original and refinished core support), NOS washer bottle and hose, NOS air cleaner and Stage 1 emission decals, NOS foam hood seals, NOS high-pressure power steering hoses, NOS radiator overflow container, NOS wiper motor and NOS valve cover air cleaner hose. "We don't find it any more difficult to put the engine in later rather than first, and actually, it helps its finish stay cleaner for a longer period of time; there was less detail cleaning to do before turning the car over to Bob," commented Keith.
A new top was purchased from Kee Auto Top and carefully installed, in conjunction with the original pump and framework; Keith noting that the pump was bench-tested during the earlier disassembly. All that it required was a cleansing and a top-off with fresh hydraulic fluid. After the top and its complement of parts were secured, work began on returning the interior to its former glory; new seat upholstery and door panels for this step were acquired from Legendary Auto Interiors.
Interior detail items followed, led by each of the gauges that had been given a close examination and refinishing before being returned to the refreshed instrument panel; even the radio was carefully examined and bench tested. As was the case with the engine bay, there was another litany of NOS parts, including, but not limited to, power window switches, ashtrays, 1971 "rivet-style" rocker sill plates (the oval "Body by Fisher" coach tags are riveted into place rather than glued), rearview mirror, door weather seals and plastic vents.
During the interior phase of the project, replacement door glass and a fresh windshield were purchased from OEM Glass. A keen eye would note the date code, which was actually obtained from the originals removed earlier and etched into the new pieces by the supplier. Another step in the restoration process not often discussed was the installation of a refinished gas tank--in this case, the trio of restorers were given NOS gas tank straps to aid in securing the unit. A new factory-style dual-exhaust system finished off the undercarriage.
There was no sense of urgency on anyone's part as the project neared completion. Great care continued when it came time to finishing the Buick's exterior appearance, and of course, there were more NOS bits, like the wheel-opening trim. The rocker molding trim was carefully taped and red rib paint precisely applied; after curing time, the molding was secured. NOS GS fender emblems were obtained and used, as were the rare NOS "wide pin" Stage 1 fender emblems and the NOS hood extension. An NOS exterior driver's side mirror, a pair of NOS front and rear side marker lamps and NOS headlamp bezels continued the trend, and proper NOS taillamp lenses accompanied the NOS "GS" and "By Buick" trunk emblems; even the license plate bracket was an NOS acquisition.
Some of the more distinguished NOS pieces that were part of the restoration of Bob's GS were the 1971-only plastic ram air hood-insert grilles. Because of their tendency to warp, even good used pieces were hard to obtain as far back as 10 years ago when these inserts were located. Add to that the nearly impossible-to-find NOS grille that topped the list; it was properly decorated with an NOS GS emblem. What minimal trim was left--most notably the bumpers--had been sent out for replating. Completing the restoration was an NOS set of chromed, 14-inch Buick five-spoke wheels shod with reproduction Goodyear Polyglas G70-14 bias-ply tires. Officially, the project wasn't actually done until just before it arrived at Dino Petrocelli's studio for our photo shoot in early November 2011.
"In the end, we deliberated whether or not we should fire it up or just push it around. Better thoughts prevailed, and we started up the engine and let it run to break in the NOS valve springs and lifters with the original camshaft," said Keith.
As mentioned earlier, the start-to-finish timeline was essential for Bob and Gran Sport Autobody for several reasons. And as Keith later commented, a number of other, non-Buick projects came and went in the 18 years that this convertible spent in-process. "In addition, Bob brought us a couple other GS projects, which were completed sooner, due to their intent," he added, referring to their status as "usable" cars. "The other benefit to the Stage 1's extended schedule, aside from allowing us to amass the huge assortment of NOS parts early in the process, was that by taking breaks to work on other material, we were able to stay fresh and focused on the end result."
But was the car owner on board with all this? "Bob was very instrumental in helping us, not only with the research, but also in acquiring the NOS parts to complete the car accordingly. His efforts made all the difference in the world in how exceptionally well it went," tells Keith of Bob's key role in the process. Despite the magnitude of this restoration, his crew remains enthusiastic about Buick renovations. But after all this, are there any NOS Buick parts left? Keith doesn't get caught up in listing what remains in Gran Sport Autobody's trove, offering only that, "We used so much NOS stuff on this car, it would be easier to list what wasn't."
OWNER'S VIEW
My attraction to Buicks started with my brother, Larry; so naturally, my first car was a Buick--a new 1970 GS, but it was a base 350 version. When I went to the dealership to pick it up, there was a GSX parked right out in front, and that's when I learned about the Stage 1. In fact, a year later, I traded in my GS for a used '70 Stage 1 and proceeded to surprise more than a few people with its power.
This 1971 Stage 1 appealed to me on many levels: Its GM of Canada documentation; the engine, of course; and the one-year-only paint, coupled with the white top and interior--what a combination. Its ownership history was also key, and I knew it would be a good car for a complete restoration. Keith and Duane deserve all the credit; they really did a fabulous job.
My advice is pretty much common knowledge: Do yourself a favor and buy the best possible example of the kind of muscle car you want, and go from there. If you settle for something that's not as complete or needs more work, it'll just take longer and cost more than you might want to spend. And consider helping out where you can, such as buying parts ahead of time."-- Bob Lindquist

This article originally appeared in the March, 2012 issue of Hemmings Muscle Machines.